Using IPv6 with prefixes shorter than a /64 on a LAN

Owen DeLong owen at
Tue Jan 25 23:17:18 CST 2011

On Jan 25, 2011, at 8:47 PM, George Bonser wrote:

>> From: Adrian Chadd 
>> Sent: Tuesday, January 25, 2011 8:37 PM
>> To: Owen DeLong
>> Cc: nanog at
>> Subject: Re: Using IPv6 with prefixes shorter than a /64 on a LAN
>> (Top-posting because the whole message is context. Oh, and I'm lazy.)
>> I do indeed love it when people break out IPv6 addressing as
>> "there's so many addresses, we'll never ever go through them!"
>> Sure, if they're only used as end-point identifiers.
> Yeah, at some point v6 IP addresses might be used for something
> completely different.  For example, rather than using a cookie to
> balance through a load balancer to get back to a server in a "sticky
> session", maybe you are redirected directly to an IP address on the
> server that represents your session.  The IP address could be
> provisioned dynamically on the server as required, the user hits the
> main URL and is "redirected" to the unique IP address representing their
> session.
There isn't a web farm big enough for that not to still work within a /64.
Since a web farm network would be a /64 anyway, this isn't an increase
in the consumption of IPv6 addresses.

> If you have a 64-bit address, each active session can easily be given
> its own unique IP.  I can see requirements at some point for servers to
> be able to handle thousands of IP addresses per interface.
Many already can.


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